A torsional vibration damper, i.e., a dual mass flywheel, is generally used for damping a torsional vibration that is generated from the transmission of power between an output shaft of an engine and an input shaft of a transmission. Typically, torsional vibration dampers include a first mass, a second mass, and a damping unit disposed between the first and second masses. The first mass is connected to the output shaft of the engine, and the second mass is connected to the input shaft of the transmission through a clutch mechanism.
Generally, a ring-shaped chamber is formed in the first mass, and the damping unit is disposed within the ring-shaped chamber. In particular, the damping unit is disposed within the ring-shaped chamber such that it can be compressed by the first and second masses in response to a relative rotation between the first and second masses.
The damping unit includes: a plurality of coil springs that are situated in series and disposed one after the other within the ring-shaped chamber; and at least one friction member that is slidably disposed between neighboring coil springs and configured to be rubbed against an inner surface of the ring-shaped chamber. In the case of a wedge-shaped friction member, the friction member may include an inner wedge-shaped friction member and an outer wedge-shaped friction member.
The ring-shaped chamber is filled with lubrication oil for lubrication of the inner surface of the ring-shaped chamber.
In the conventional torsional vibration damper, friction between the outer and inner wedge-shaped friction members is allowed within a limited range, and therefore good damping characteristics cannot be achieved. In addition, while the coil spring is returned to its original state from a compressed state, the inner and outer wedge-shaped friction members can be deviated from each other, and this may cause the torsional vibration damper to deteriorate.
The information disclosed in this section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known in this country to a person of ordinary skill in the art.